Synoptic transects on the distribution of trace elements (Hg, Pb, Cd, Cu, Ni, Zn, Co, Mn, Fe, and Al) in surface waters of the Northern- and Southern East Atlantic

Surface seawater samples were taken in the framework of the GEOTRACES program on "POLARSTERN" expedition ANT XXIII/1 in the Eastern Atlantic in 2005 to study the distribution of the trace elements Hg (mercury), Pb (lead), Cd (cadmium), Cu (copper), Ni (nickel), Zn (zinc), Co (cobalt), Mn (manganese), Fe (iron), and Al (aluminium). With the exception of Hg, results were compared to earlier datasets from 1989 to 1990. The particulate fraction averaged over the transect was calculated to be 49% for Cd, 23% for Mn and 50% for Fe indicating a release of these TEI's (trace elements and their isotopes) from a leachable SPM fraction in the stored and acidified samples. Total Pb concentrations ranged between 5 and 20 pmol kg(-1) in 2005 with highest values in the ITCZ (intertropical convergence zone). In 1989 Pb concentrations were twice as high in the region of the ITCZ, while by a factor of 10-15 higher values were obtained in the North Atlantic. Total Cd and Co are dominated, by different seasonal upwelling regimes (Equatorial upwelling, Guinea Dome, Angola Dome). Total Cu, Ni, Fe, Mn and Al show nearly identical concentrations in 1990 and 2005. For total manganese and aluminium strong maxima (3-4 nmol kg(-1) and 55 nmol kg(-1) respectively) are observed between 23 degrees N and 0 degrees, while the Fe maximum (6-9 nmol kg(-1)) is located at 7 degrees N. Total Hg concentrations ranged between 0.5 and 4.5 pmol kg(-1). (C) 2010 Elsevier B.V. All rights reserved.